He battered his former step-daughter so hard over the head with a saucepan that he left her bruised and bleeding on the floor, and the pan was so badly broken it had to be thrown away.
His first wife had to wear make-up on her wedding day to hide a black eye he had given her.
He has been found guilty of multiple violent attacks against his three ex-wives and his former stepdaughter - and yet Bill Walker may still, perfectly legally, call himself an MSP and draw a taxpayer-funded salary.
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That this convicted violent offender has not resigned his seat and cannot be forced to do so under existing parliamentary rules is an affront to women and a disgrace to Holyrood. He faces no more than a year in jail and, under the law, it requires a jail sentence of more than a year before an MSP may be disqualified. The prospect therefore looms that a man convicted of blighting women's lives with repeated acts of abuse could continue to act as an MSP. That can scarcely be tolerated.
The rules governing who may stand for Parliament should not be so draconian as to disqualify every individual with the slightest blemish on their record, but the public must be confident that safeguards are in place to ensure those convicted of reviled crimes will be ejected. Scottish Women's Aid rightly argues that length of sentence is too blunt an instrument for measuring the severity of an offence and that the type of crime should also be taken into consideration.
There is strong cross-party support for reform, so it is frustrating indeed that Holyrood does not have the power to change the rules. Westminster could - and should - do so, but the Scottish Parliament does not have to wait: it may be able to bring forward a recall bill, to give constituents the power to eject an MSP. That would ultimately ensure voters were never again powerless to remove such a manifestly unsuitable individual from Parliament.
It is not only Holyrood that is coming under scrutiny over this case, however, it is also the SNP. Following allegations about Walker's abusive behaviour in The Herald's sister paper the Sunday Herald last year, the SNP expelled Bill Walker from its ranks, after the party's disciplinary committee ruled that he had not declared the allegations during the Holyrood candidate process.
It also strengthened vetting procedures, which is enouraging.
Yet none of that explains how the pre-existing vetting procedures allowed for Walker to be selected as a parliamentary candidate. Walker's former brother-in-law visited Nicola Sturgeon's constituency office in 2008 highlighting credible concerns about the abusive behaviour. Walker still went on to be selected by the SNP to fight the 2011 election. He won the seat and up until now has refused to give it up.
Party vetting procedures exist precisely to ensure that only upstanding individuals stand for office. Had they worked better in this case, this abusive individual might never have set foot in Holyrood.